<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: pink;
            position: absolute;
        }
    </style>
</head>
<body>
    <div></div>
    <script>
        var div = document.querySelector('div');
        var move = setInterval(function(){
            if(div.offsetLeft >=400){
                clearInterval(move);
            }else{
                div.style.left =  div.offsetLeft + 1 + 'px';
                console.log(div.style.left);
            }
        },30);
    </script>
</body>
</html>